The blood-ocular barrier (BOB) provides a shield for the ocular tissues and fluids, preventing the transport of certain molecules from the plasma into the eye. This is generally a favored feature of the BOB, except when the transport of therapeutic or diagnostic agents to the eye is desired. The BOB is comprised of capillary endothelial cells connected by tight junctions. Although alterations in the permeability of the barrier may occur in certain diseases, as well as from trauma, surgery or certain pharmacologic agents, it is generally not sufficient to permit adequate quantities of a therapeutic agent into the eye.
Currently, agents are administered for delivery to the eye by a number of methods including systemic administration (intravenous), local application of an agent-containing solution, placement of a porous component in contact with the eye for sustained release of an agent, or insertion of an implant containing an agent. These delivery methods are often inadequate due to the limited ability of the agent itself to penetrate the BOB. In other cases, agents are administered by direct injection into the eye. This means is inadequate due to a high level of discomfort, risk of injury, and expense of treatment.
The need exists for an effective and non-invasive means for delivering adequate quantities of a therapeutic or diagnostic agent into the eye and across the BOB in order to provide better treatment and diagnosis of ocular diseases.